The invention relates to a circuit breaker for breaking a circuit subject to a short circuit current, in which the natural development of the arc which appears on opening of a pair of contacts placed in a chamber, and moves along a deflecting conductor is assisted and accelerated by a magnetic field which is created by at least one loop conducting the short circuit current. The loop is placed outside the chamber in a plane substantially parallel to that which passes through the deflector and through these contacts.
It relates more particularly to a circuit breaker of a type similar to that described in patent specifications EP 231 600, in which the conducting loop comprises:
a first end portion adapted to be electrically connected to the fixed contact; PA1 a tongue extending the first portion so as to form the deflecting conductor; and PA1 a second end portion, placed in the alignment of the tongue and joined directly or indirectly to a connection terminal of the apparatus which is fitted with the circuit breaker.
In circuit breakers of the above type, arc extinction is promoted by means of a magnetic field which is established in the current path for accelerating swelling and hastening destabilization of the arc. It is thus possible to manufacture current limiter apparatuses of reduced size.
The construction of current loops is a relatively costly operation to the extent that it requires either the assembly of several elements or the stamping out and bending of stamped conducting pieces, whose development in the plane of the metal sheet from which they are taken badly uses the available area; such a stamping technique is however advantageous because it simplifies the mounting of apparatus manufactured on a very large scale, by avoiding subsequent welding and/or assembly operations.
It is an object of the invention to provide a circuit breaker such as defined above, in which the shaping of the current loop will meet the following requirements: simplicity, ease of assembly, reduced width and reduced manufacturing cost.